Reel-to-reel magnetic tapes and one-half inch and one-quarter inch magnetic tape data cartridges are commonly used for the storage of electronic data signals. A typical tape data cartridge comprises a metal baseplate with pins extending upwardly from the plate to support corner rollers, reel hubs, a drive roller, and posts which extend upwardly to support tape guides. Typically, the wails and top of the cartridge are made of polymeric material and the top usually includes a spring to limit the vertical movement of the reel hubs. The tape alignment must be precise for the recording or the retrieving of the desired data signals: on the tape. Therefore, it is very important that the pins and posts maintain their alignment during cartridge use. This is in clear distinction to tape cassettes which merely house a length of tape on hubs that require external support for movement of tape over a tape path that is determined by external tape guides. Tape cartridges therefore are essentially self-contained machines which require precision placement and elevational orientation of internal tape guides and internal supporting pins for rotatable components.
With the metal baseplate currently used, the pins are rigidly secured to the metal baseplate and the metal baseplate provides sufficient rigidity to support the various components received on the pins such that the tape does not become misaligned or dislodged during use. However, the metal baseplate is a major contributing expense to the overall cost of the cartridge. The use of a polymeric material for the baseplate typically does not achieve the equivalent structural strength required for successful use of the cartridge. If such polymeric material is too hard, inserting the pins into the material presents an additional problem of stress and fatigue cracks commonly occurring where the pins are inserted. Conversely, too soft a polymeric material imparts an elasticity to the pins received in the material which results in misalignment of the tape and associated components in use.